RequiredFieldValidator for an optional field

Hi,

Please find the attached file.

If i select Add New radio button, RadEditor control will be displayed.If I select Link to existing radio button, URL field will be displayed. If user select Add New then RadEditor is a mandatory field. If user select Link to Existing then URL field is the mandatory field. How to check this?

I put 2 RequiredFieldValidator controls and by default i make it enabled = false then on click of submit button i enabled as below but it is not working:

  protected void btnSubmit_Click(object sender, EventArgs arg)
        {
            if (radioAddNew.Checked)
                RequiredFieldValidatorRadEditorContent.Enabled = true;
            else if (radioLinkToExisting.Checked)
                RequiredFieldValidatorURL.Enabled = true;

            if (Page.IsValid)
            {
                  //other code
      }
      }

Any other way to do this?


Thanks,
Requiredfieldvalidator.jpg